• Journal of the Korean Geotechnical Society
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• v.22 no.1
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• pp.25-34
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• 2006

In this study an effective stress numerical procedure is used to assess the results of dynamic centrifuge tests under high effective stress. The centrifuge models consist of loose Nevada sand with an initial vertical effective stress of 380kPa at depth, and they are modeled as a one-dimentional soil column. Liquefaction occurred up to 37m or 22m at depth, and the onset of liquefaction triggering was opposite to the conventional liquefaction evaluation procedure. In other words, liquefaction occurs first at the top and propagates downward as shaking continues. The results observed in centrifuge tests are reasonably predicted by the effective stress model. It is noted that the degree of initial saturation and additional densification at depth arising from the application of the high acceleration field play a key role in capturing the results of dynamic centrifuge tests.

• Culinary science and hospitality research
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• v.14 no.4
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• pp.339-356
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• 2008

The purpose of this study is to provide the developmental basic data of a change in shift work types by making a self-administered survey of the effect of commitment by shift work and the open kitchen system on job satisfaction and job stress, and mutual relation between variables on 287 cooks in luxury hotels. Analysis showed that the operation of the shift work system was effective in reducing the internal stress of the cooks, their external stress, or their self-uncertainty on the job, and the business by the open kitchen system was effective in raising self-esteem. In addition, job commitment by shift work and the open kitchen system were effective in promoting the job satisfaction of employees, interpersonal relations, promotion, benefits and wages. Consequently, the decrease of external and internal stress or self-uncertainty and the improvement of job satisfaction can be connected with the increase of productivity or cost reduction. Therefore, the open kitchen system should be properly applied to the shift work system, along with sanitation, safety and the periodic checkup of kitchen.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.1
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• pp.1-7
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• 2021

This paper presents sensitivity analysis results of strain on notches under cycling loading to 2-D finite element density considering plasticity. Cylindrical notched specimens having some stress concentrations were modeled with 2-D axisymmetrical finite element having various finite element densities. Elasto-plastic finite element analysis was performed for the various finite element models subjected to cycling loading considering plasticity. The finite element analysis results were compared to investigate sensitivity of the finite element analysis variables such as von-Mises effective stress, accumulated equivalent plastic strain, and equivalent plastic strain to 2-D finite element density. As a result of the comparison, it was found that the accumulated equivalent plastic strain is more sensitive than the others whereas the von-Mises effective stress is much less sensitive.

• Journal of muscle and joint health
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• v.28 no.1
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• pp.61-69
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• 2021

Purpose: This study investigated the mediating effect of perceived stress in the relationship between subjective health and depression in patients with coronary artery disease. Methods: This secondary analysis study used data from the 2016-2018 Korea National Health and Nutrition Examination Survey (KNHANES). Study participants included 466 patients over 20 years of age with coronary artery disease. Measures included questions about general characteristics, subjective health, perceived stress, and depression. The data were analyzed using complex sample design, descriptive analysis, Rao-Scott ��2 statistic, and multivariate logistic regression analysis with the SPSS 24.0 program. Results: Subjective health influenced depression, and perceived stress partially mediated it. Conclusion: To prevent depression in patients with coronary artery disease, it is necessary to develop effective stress management strategies.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.321-337
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• 2000

Dental caries, one of the most frequent dental disease, become larger because it can be thought as a simple disease. Further more, it can progress to unexpected root canal therapy with fabrication of crown that needs reduction of tooth structure. Base is required in a large caries and ZOE, ZPC, glass ionomer are used frequently as base material. They, with restorative material, can affect the longevity of the restoration. In this study, we assume that the mandibular 1st molar has deep class I cavity. So, installing the 3 base material, 3 kinds of fillings were restored over the base as follows; 1) amalgam only, 2) amalgam with ZPC, 3) amalgam with ZOE, 4) amalgam with GI cement, 5) gold inlay with ZPC, 6) gold inlay with GI cement, 7) composite resin only, 8) composite resin with GI cement. After develop the 3-dimensional model for finite element analysis, we observe the distribution of stress and temperature with force of 500N to apical direction at 3 point on occlusal surface and temperature of 55 degree, 15 degree on entire surface. The analyzed results were as follow : 1. Principal stress produced at the interface of base, dentin, cavity wall was smallest in case of using GI cement as base material under the amalgam. 2. Principal stress produced at the interface of base, dentin, cavity wall was smaller in case of using GI cement as a base material than ZPC under gold inlay. 3. Composite resin-filled tooth showed stress distributed over entire tooth structure. In other words, there was little concentration of stress. 4. ZOE was the most effective base material against hot stimuli under the amalgam and GI cement was the next. In case of gold inlay, GI cement was more effective than ZPC. 5. Composite resin has the small coefficient of thermal conductivity. So, composite resin filling is the most effective insulating material.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.334-344
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• 2007

This paper performed a comprehensive evaluation of the results of the 2007 Ground Response Analysis Round Robin Test, at which 14 institutions and individuals participated. The submitted results showed significant discrepancies. The main reason for this difference has been attributed to the dispersion in the estimated shear wave velocity profiles and dynamic soil curves. It is therefore concluded that accurate evaluation of the material properties is of primary importance for reliable estimation of the ground vibration. Evaluation of the effect of the analysis method showed that the equivalent linear analysis overestimates the peak ground acceleration, but overall the results are similar to a total stress nonlinear analysis. However, the total and effective stress nonlinear analyses show distinct discrepancies, the effective stress analyses consistently resulting in a lower response due to the development of the excess pore water pressure and thus softer response.

• Structural Engineering and Mechanics
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• v.4 no.4
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• pp.397-413
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• 1996

In this paper the elastic post-buckling behaviour of plates under non-uniform compressive edge stress is investigated. The compatibility differential equations is first solved analytically and then an approximate solution of the equilibrium equation is obtained using the Galerkin method. Explicit expressions are derived for the load-deflection, ultimate strength and membrane stress distributions. Analytical effective width formulations, based on the characteristics of the stress field of the buckled plate, are proposed for this general loading condition. The predicted load-deflection expression is compared with independent test results. Results are also presented detailing the load-deflection behaviour and stress distribution for various aspect ratios.

• Journal of Welding and Joining
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• v.16 no.2
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• pp.111-121
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• 1998

It is well recognized that a excessive temperature gradient from the junction of head to skirt in axial direction in a hot pressure vessel can cause unpredicted high thermal stress at the junction and/or in axial direction of a skirt. this thermal stress resulting from axial thermal gradient may be a major cause of unsoundness of structural integrity. In case of cyclic operation of hot pressure vessels, the thermal stress becomes one of the primary design consideration because of the possibility of fracture as a result of cyclic thermal fatigue and progressively incremental plastic deformation. To perform thermal stress analysis of the junction and cylindrical skirt of a vessel, or, at least, to inspect quantitatively the magnitude and effect of thermal stress, the temperature profile of the vessel and skirt must be known. This paper demonstrated the temperature distribution and thermal stress analysis for the junction of skirt to head using F.E. analysis. Effect of air pocket in crotch space was quantitatively investigated to minimize the temperature gradient causing the thermal stress in axial direction. Effect of the skirt height on thermal stresses was also studied. Analysis results were compared with theoretical formulas to verify th applicability to the strength calculation in design field.

• Journal of Korean Academy of Nursing
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• v.48 no.5
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• pp.578-587
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• 2018

Purpose: This study aimed to understand the mechanisms of decision regret and stress of family surrogates' end-of-life decision making using an exploratory path model. In particular, the research identified the direct effects of perceptions of uncertainty and effective decisions on decision regret and stress, and examined the indirect effects of being informed, having clear values, and being supported for decision regret and the stress of end-of-life decision making through the mediating variables of perceptions of uncertainty and effective decisions. Methods: Data were collected from 102 family surrogates who had participated in end-of-life decision making for patients with terminal cancer in a tertiary hospital. Results: Perception of effective decisions was a significant direct predictor of decision regret, and uncertainty was a significant predictor of stress among the participants. Being informed, having clear values, and being supported had a significant indirect influence on decision regret through the perception of effective decisions among family surrogates. However, only having clear values had a significant indirect influence on stress through the perception of uncertainty. The model explained 63.0% of decision regret and 20.0% of stress among the participants and showed a good fit with the data, ${\chi}^2=12.40$ (df=8, p=.134), TLI=.97, and RMSEA=.07. Conclusion: Nurses can support family surrogates in end-of-life decision-making processes to decrease their decision regret by providing information about end-of-life care choices, clarifying personal values, and supporting the decision-making process, and to relieve their stress by facilitating the clarification of personal values.

• Structural Engineering and Mechanics
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• v.67 no.5
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• pp.527-544
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• 2018

In this paper, the effect of homogenization models on stress analysis is presented for functionally graded plates (FGMs). The derivation of the effective elastic proprieties of the FGMs, which are a combination of both ceramic and metallic phase materials, is of most of importance. The majority of studies in the last decade, the Voigt homogenization model explored to derive the effective elastic proprieties of FGMs at macroscopic-scale in order to study their mechanical responses. In this work, various homogenization models were used to derive the effective elastic proprieties of FGMs. The effect of these models on the stress analysis have also been presented and discussed through a comparative study. So as to show this effect, a refined plate theory is formulated and evaluated, the number of unknowns and governing equations were reduced by dividing the transverse displacement into both bending and shear parts. Based on sinusoidal variation of displacement field trough the thickness, the shear stresses on top and bottom surfaces of plate were vanished and the shear correction factor was avoided. Governing equations of equilibrium were derived from the principle of virtual displacements. Analytical solutions of the stress analysis were obtained for simply supported FGM plates. The obtained results of the displacements and stresses were compared with those predicted by other plate theories available in the literature. This study demonstrates the sensitivity of the obtained results to different homogenization models and that the results generated may vary considerably from one theory to another. Finally, this study offers benchmark results for the multi-scale analysis of functionally graded plates.